1. What is the role of proteins in the body?
Proteins perform several main roles in our body:
They are the material for the construction of all cells, tissues and organs;
Provide immunity to the body and act as antibodies;
Participate in the digestive process and energy metabolism.
2. What foods are rich in proteins?
Meat, poultry, fish and seafood, milk and dairy products, cheese, eggs, fruits (apples, pears and pineapples, kiwi, mango, passion fruit, lychee, etc.).
Questions
1. What substances are called proteins or proteins?
Proteins are natural organic substances consisting of amino acids and play a fundamental role in the life of the body.
2. What is the primary structure of a protein?
The sequence of amino acids within a polypeptide chain represents the primary structure of the protein. It is unique to any protein and determines its shape, properties and functions.
3. How are secondary, tertiary and quaternary protein structures formed?
As a result of the formation of hydrogen bonds between CO and NH groups of different amino acid residues of the polypeptide chain, a helix is formed. Hydrogen bonds are weak, but together they provide a fairly strong structure. This helix is the secondary structure of the protein.
Tertiary structure is a three-dimensional spatial “packing” of a polypeptide chain. The result is a bizarre, but specific configuration for each protein - a globule. The strength of the tertiary structure is ensured by the various bonds that arise between amino acid radicals.
The quaternary structure results from the combination of several macromolecules (globules) with a tertiary structure into a complex complex. For example, hemoglobin in human blood is a complex of four protein macromolecules.
4. What is protein denaturation?
Violation of the natural structure of a protein is called denaturation. It can occur under the influence of temperature, chemicals, radiant energy and other factors.
5. On what basis are proteins divided into simple and complex?
Simple proteins consist only of amino acids. Complex proteins also contain carbohydrates (glycoproteins), fats (lipoproteins), nucleic acids (nucleoproteins), etc.
Quests
You know that the white of a chicken egg consists mainly of proteins. Think about what explains the change in the protein structure of a boiled egg. Give other examples you know of where protein structure can change.
As a result of exposure to high temperatures, the protein denatures the egg. As a result of this, the protein loses its properties (transparency, etc.). Any heat treatment of food (boiling, frying, baking) leads to denaturation of proteins. As a result, proteins become more accessible to the action of digestive enzymes, but they themselves lose functional activity.
>> Composition and structure of proteins
Composition and structure of proteins.
1. What is the role of proteins in the body?
2. What foods are rich in proteins?
Among organic substances squirrels, or proteins, are the most numerous, most diverse and of paramount importance biopolymers. They account for 50-80% of the dry mass of the cell.
Protein molecules are large in size, which is why they are called macromolecules. In addition to carbon, oxygen, hydrogen and nitrogen, proteins may contain sulfur, phosphorus and iron. Proteins differ from each other in the number (from one hundred to several thousand), composition and sequence of monomers. Protein monomers are amino acids (Fig. 5).
An infinite variety of proteins is created by different combinations of just 20 amino acids. Each amino acid has its own name, special structure and properties. Their general formula can be presented as follows.
An amino acid molecule consists of two parts identical to all amino acids, one of which is an amino group (-NH2) with basic properties, the other is a carboxyl group (-COOH) with acidic properties. The part of the molecule called the radical (R) has a different structure for different amino acids. The presence of basic and acidic groups in one amino acid molecule determines their high reactivity. Through these groups, amino acids are combined to form proteins. In this case, a water molecule appears, and the released electrons form a peptide bond. Therefore, proteins are called polypeptides.
Protein molecules can have different spatial configurations, and in their structure there are four levels of structural organizations(Fig. 6).
The sequence of amino acids within a polypeptide chain represents the primary structure of the protein. It is unique to any protein and determines its shape, properties and functions.
Most proteins have the shape of a helix as a result of the formation of hydrogen bonds between the -CO- and -NH-groups of different amino acid residues of the polypeptide chain. Hydrogen bonds are weak, but taken together they provide a fairly strong structure. This helix is the secondary structure of the protein.
Tertiary structure is the three-dimensional spatial “packing” of a polypeptide chain. The result is a bizarre, but specific configuration for each protein - a globule. The strength of the tertiary structure is ensured by the various bonds that arise between amino acid radicals.
Quaternary structure is not characteristic of all proteins. It arises as a result of the combination of several macromolecules with a tertiary structure into a complex complex. For example, hemoglobin blood human is a complex of four protein macromolecules (Fig. 7).
This complexity of the structure of protein molecules is associated with the diversity of functions inherent in these biopolymers.
Violation of the natural structure of the protein is called denaturation (Fig. 8). It can occur under the influence of temperature, chemicals, radiant energy and other factors. With a weak impact, only the quaternary structure disintegrates, with a stronger one - the tertiary, and then the secondary, and the protein remains in the form of a polypeptide chain.
This process is partially reversible: if the primary structure is not destroyed, then the denatured protein is able to restore its structure. It follows that all structural features of a protein macromolecule are determined by its primary structure.
In addition to simple proteins consisting only of amino acids, there are also complex proteins, which may include carbohydrates(glycoproteins), fats (lipoproteins), nucleic acids (nucleoproteins), etc.
The role of proteins in the life of a cell is enormous. Modern biology has shown that similarities and differences organisms determined ultimately by a set of proteins. The closer organisms are to each other in systematic position, the more similar their proteins are.
Proteins, or proteins. Simple and complex proteins. Amino acids. Polypeptide. Primary, secondary, tertiary and quaternary structures of proteins.
1. What substances are called proteins, or proteins?
2. What is the primary structure of a protein?
3. How are secondary, tertiary and quaternary protein structures formed?
4. What is protein denaturation?
5. On what basis are proteins divided into simple and complex?
Kamensky A. A., Kriksunov E. V., Pasechnik V. V. Biology 9th grade
Submitted by readers from the website
1. Why are proteins considered polymers?
Answer. Proteins are polymers, that is, molecules built like chains from repeating monomer units, or subunits, consisting of amino acids connected in a certain sequence by a peptide bond. They are the basic and necessary components of all organisms.
There are simple proteins (proteins) and complex proteins (proteids). Proteins are proteins whose molecules contain only protein components. When they are completely hydrolyzed, amino acids are formed.
Proteids are complex proteins whose molecules differ significantly from protein molecules in that, in addition to the protein component itself, they contain a low molecular weight component of a non-protein nature
2. What functions of proteins do you know?
Answer. Proteins perform the following functions: construction, energy, catalytic, protective, transport, contractile, signaling and others.
Questions after § 11
1. What substances are called proteins?
Answer. Proteins, or proteins, are biological polymers whose monomers are amino acids. All amino acids have an amino group (-NH2) and a carboxyl group (-COOH) and differ in the structure and properties of radicals. Amino acids are linked to each other by peptide bonds, which is why proteins are also called polypeptides.
Answer. Protein molecules can take on different spatial forms - conformations, which represent four levels of their organization. The linear sequence of amino acids within a polypeptide chain represents the primary structure of a protein. It is unique to any protein and determines its shape, properties and functions.
3. How are secondary, tertiary and quaternary protein structures formed?
Answer. The secondary structure of a protein is formed by the formation of hydrogen bonds between -CO- and -NH- groups. In this case, the polypeptide chain twists into a spiral. The helix can acquire a globule configuration, since various bonds arise between amino acid radicals in the helix. A globule is the tertiary structure of a protein. If several globules combine into a single complex complex, a quaternary structure arises. For example, hemoglobin in human blood is formed by four globules.
4. What is protein denaturation?
Answer. Violation of the natural structure of a protein is called denaturation. Under the influence of a number of factors (chemical, radioactive, temperature, etc.), the quaternary, tertiary and secondary structures of the protein can be destroyed. If the effect of the factor ceases, the protein can restore its structure. If the effect of the factor increases, the primary structure of the protein - the polypeptide chain - is also destroyed. This is an irreversible process - the protein cannot restore its structure
5. On what basis are proteins divided into simple and complex?
Answer. Simple proteins consist solely of amino acids. Complex proteins may include other organic substances: carbohydrates (then called glycoproteins), fats (lipoproteins), nucleic acids (nucleoproteins).
6. What functions of proteins do you know?
Answer. Construction (plastic) function. Proteins are a structural component of biological membranes and cell organelles, and are also part of the supporting structures of the body, hair, nails, and blood vessels. Enzymatic function. Proteins serve as enzymes, that is, biological catalysts that accelerate the rate of biochemical reactions tens and hundreds of millions of times. An example is amylase, which breaks down starch into monosaccharides. Contractile (motor) function. It is performed by special contractile proteins that ensure the movement of cells and intracellular structures. Thanks to them, chromosomes move during cell division, and flagella and cilia move protozoan cells. The contractile properties of the proteins actin and myosin underlie muscle function. Transport function. Proteins are involved in the transport of molecules and ions within the body (hemoglobin carries oxygen from the lungs to organs and tissues, serum albumin is involved in the transport of fatty acids). Protective function. It consists of protecting the body from damage and invasion of foreign proteins and bacteria. Antibody proteins produced by lymphocytes create the body's defense against foreign infection; thrombin and fibrin are involved in the formation of a blood clot, thereby helping the body avoid large blood losses. Regulatory function. It is performed by hormone proteins. They participate in the regulation of cell activity and all life processes of the body. Thus, insulin regulates blood sugar levels and maintains them at a certain level. Signal function. Proteins embedded in the cell membrane are capable of changing their structure in response to irritation. Thus, signals are transmitted from the external environment into the cell. Energy function. It is realized by proteins extremely rarely. With complete breakdown of 1 g of protein, 17.6 kJ of energy can be released. However, proteins are a very valuable compound for the body. Therefore, protein breakdown usually occurs to amino acids, from which new polypeptide chains are built. Hormone proteins regulate the activity of the cell and all life processes of the body. Thus, in the human body, somatotropin is involved in the regulation of body growth, insulin maintains the blood glucose level at a constant level.
7. What role do hormone proteins play?
Answer. The regulatory function is inherent in hormone proteins (regulators). They regulate various physiological processes. For example, the most well-known hormone is insulin, which regulates blood glucose levels. When there is not enough insulin in the body, a disease known as diabetes mellitus occurs.
8. What function do enzyme proteins perform?
Answer. Enzymes are biological catalysts, that is, they accelerate chemical reactions hundreds of millions of times. Enzymes have strict specificity for the substance that reacts. Each reaction is catalyzed by its own enzyme.
9. Why are proteins rarely used as an energy source?
Answer. Amino acid protein monomers are valuable raw materials for the construction of new protein molecules. Therefore, complete breakdown of polypeptides into inorganic substances rarely occurs. Consequently, the energetic function, which consists in releasing energy upon complete breakdown, is performed by proteins quite rarely.
Egg white is a typical protein. Find out what will happen to it if it is exposed to water, alcohol, acetone, acid, alkali, vegetable oil, high temperature, etc.
Answer. As a result of the action of high temperature on the egg white, protein denaturation will occur. When exposed to alcohol, acetone, acids or alkalis, approximately the same thing happens: the protein coagulates. This is a process in which the tertiary and quaternary structure of a protein is disrupted due to the rupture of hydrogen and ionic bonds.
In water and vegetable oil, protein retains its structure.
Grind the raw potato tuber to a pulp. Take three test tubes and put a small amount of chopped potatoes into each.
Place the first test tube in the freezer of the refrigerator, the second on the bottom shelf of the refrigerator, and the third in a jar of warm water (t = 40 °C). After 30 minutes, remove the test tubes and drop a small amount of hydrogen peroxide into each. Observe what happens in each test tube. Explain your results
Answer. This experiment illustrates the activity of the enzyme catalase in a living cell on hydrogen peroxide. As a result of the reaction, oxygen is released. The dynamics of the release of bubbles can be used to judge the activity of the enzyme.
The experience allowed us to record the following results:
Catalase activity depends on temperature:
1. Test tube 1: there are no bubbles - this is because at low temperatures the potato cells collapsed.
2. Test tube 2: there are a small number of bubbles - because the activity of the enzyme at low temperatures is low.
3. Test tube 3: there are a lot of bubbles, the temperature is optimal, catalase is very active.
Drop a few drops of water into the first test tube with potatoes, a few drops of acid (table vinegar) into the second, and alkali into the third.
Observe what happens in each test tube. Explain your results. Draw conclusions.
Answer. When water is added, nothing happens, when acid is added, some darkening occurs, when alkali is added, “foaming” occurs - alkaline hydrolysis.
Question 1. What substances are called proteins or proteins?
Proteins (proteins)- these are heteropolymers consisting of 20 different monomers - natural alpha amino acids. Proteins are irregular polymers.
The general structure of an amino acid can be represented as follows:
R-C(NH 2)-COOH. All amino acids have an amino group (-MH2) and a carboxyl group (-COOH) and differ in the structure and properties of radicals. Amino acids in a protein are linked by a peptide bond
-N(H)-C(=O) bond, which is why proteins are also called peptides.
Question 2. What is the primary structure of a protein?
In a protein molecule, amino acids are linked to each other by a peptide bond between carbon and nitrogen atoms. In the structure of a protein molecule, a primary structure is distinguished - the sequence of amino acid residues.
Question 3. How are the secondary, tertiary and quaternary structures of a protein formed?
The secondary structure of a protein is typically a helical structure (alpha helix) held together by multiple hydrogen bonds that occur between the closely spaced C=O and NH groups. Another type of secondary structure is the beta layer, or folded layer; these are two parallel polypeptide chains connected by hydrogen bonds perpendicular to the chains.
The tertiary structure of a protein molecule is a spatial configuration resembling a compact globule. It is supported by ionic, hydrogen and disulfide (S=S) bonds, as well as hydrophobic interactions.
The quaternary structure is formed by the interaction of several globules, which are combined into a complex (for example, the hemoglobin molecule consists of four such subunits).
Question 4: What is protein denaturation?
The loss of a protein molecule's structure is called denaturation; it can be caused by increased temperature, dehydration, radiation, etc. If the primary structure is not disturbed during denaturation, then when normal conditions are restored, the protein structure is completely recreated. If the effect of the factor increases, the primary structure of the protein - the polypeptide chain - is also destroyed. This is an irreversible process - the protein cannot restore its structure. For example, at high temperatures (above 42oC) in the human body, many proteins denature irreversibly.
Question 5. On what basis are proteins divided into simple and complex?
Simple proteins (proteins) consist exclusively of amino acids (albumin, globulins, keratin, collagen, histone and others). Complex proteins may include other organic substances: carbohydrates (then called glycoproteins), fats (lipoproteins), nucleic acids (nucleoproteins), phosphoric acid (phosphoproteins); when a protein is combined with any colored substance, so-called chromoproteins are formed. Of the chromoproteins, the most studied is hemoglobin, the coloring substance of red blood cells (erythrocytes).
Urine egg is a highly valuable product; it is used in therapeutic and preventive nutrition. The chemical composition of the egg depends on the type of bird, the time of year when the egg was laid, and the food. Chicken and turkey eggs are used in therapeutic nutrition. When the egg is just laid, its temperature is 40 degrees, and the egg must be stored at a temperature of +5 degrees. Within 5 days after the egg is laid, it is considered dietary. On average, an egg weighs 53 g, of which the white weighs 31 g, the yolk weighs 16 g and the shell weighs 6 g. The topic of our article today is “Chicken egg white, properties.”
Sources: egg, meat, dairy, seafood, rye, almonds, cashew kernels, sunflower seeds, chickpeas, beans. Sources: egg, fish, seafood, meat, oats, oatmeal, sprouts, nuts, kernels, sesame seeds, lentils, soy, avocado. Sources: egg, fish, seafood, meat, dairy products, wheat germ, oatmeal, nuts, almonds, legumes.
Sources: dairy, meat, poultry, fish, seafood, wheatgrass, oatmeal, nuts, lentils, soybeans. Sources: white eggs, meat, poultry, grain sprouts, peanuts, sesame seeds. Listed below are some amino acids that are not essential but are often deficient in the body.
A chicken egg consists of yolk and white. The yolk contains proteins, fats and cholesterol. The fats found in the yolk are harmless; they are polyunsaturated. Protein consists of 90% water and 10% proteins, does not contain cholesterol.
Eggs are rich in vitamins and mineral salts necessary for our body:
1.Niacin – necessary for the formation of sex hormones and for nourishing the brain.
Sources: liver, dairy products, cabbage, avocado, wheat germ. Sources: cheese, meat, poultry, eggs, fish, shellfish, nuts, kernels, chocolate, peas, soy, avocado, garlic and ginseng. Sources: herring, avocado, meat, almonds, sesame, chickpeas, pecans. Biological value of protein.
The body can make best use of protein from food if it is very similar to the body's own protein - in terms of structure and ratio of essential amino acids. The more amino acids present, the better. 9 essential amino acids that we must take in food to finally produce all 20 amino acids that the body needs.
2.Vitamin K – ensures blood clotting.
3. Choline – removes poisons from the liver and serves to improve memory.
4.Folic acid and biotin, which prevent birth defects in children.
5. The egg contains 200 - 250 g of phosphorus, 60 mg of iron, 2-3 mg of iron.
6.The egg also contains copper, iodine and cobalt.
7. 100 g of egg contains vitamin B2 - 0.5 mg, B6 - 1-2 mg, B12, E - 2 mg. They also contain vitamin D 180-250 IU, which is second only to fish oil.
The high quality of protein-rich food depends on the quantity and composition of essential amino acids and is referred to as “biological value”. This value is generally higher for animal proteins than for plant proteins. This is why it is very important for vegetarians to consume protein that has high biological value. This is followed by a review of the biological value of various protein sources.
For rapid recovery in athletes and patients, whey protein is actually an effective source of protein. It is best to choose an isolate or a product that has been made using microfiltration technology. When different foods are consumed together with a protein with a different biological value, the biological value can be increased by the combination. Good combinations are, for example.
8. Egg yolk is the richest in mineral salts and vitamins.
Chicken egg white contains minerals, amino acids, carbohydrates, and protein. Without protein, cell formation and renewal is impossible. Chicken egg white is taken as the standard of biological value for humans.
Eggs are a nutritious product and at the same time low in calories. Chicken egg white is a low-calorie source of protein. 100 g of egg white contains 45 kcal and 11 g of protein. For comparison, for example, 100 g of milk contains 69 kcal and 4 g of protein, and 100 g of beef contains 218 kcal and 17 g of protein. Protein is absorbed by the body by 97%, without producing waste and immediately goes into the formation of antibodies. It is the egg whites that help restore strength and strengthen the immune system. Soft-boiled eggs are most favorable for digestion. Yolk calcium is very well absorbed by the body.
Protein may have high biological value, but how well is it absorbed by the body? In general, we can say that animal protein with high biological value also has high net protein utilization. This means that only a few percent cannot be digested or absorbed by the body.
The reason is that plant protein contains quite a lot of anti-nutrients. Phytic acid in bread and nuts. Trypsins and saponins in soybeans. Soybean has very high biological value, but anti-nutrients are of lower use.
Fresh raw egg white is used for inflammatory diseases. The protein does not irritate the gastric mucosa and leaves it quickly, which is why chicken protein is used for peptic ulcers. It can also be used for chronic pancreatinitis.
In case of atherosclerosis, it is advisable to limit the consumption of eggs due to their significant fat content. Egg yolk contains an average cholesterol content of 1.5–2% and lecithin 10%. The predominance of lecithin over cholesterol makes it possible not to completely exclude eggs from the diet for atherosclerosis.
Lectins in legumes. But this is not an absolute commandment. Animal protein, such as milk, also contains a strong anti-nutrient, namely casein. As you have read, animal sources contain, compared to plant proteins, mostly proteins that can be better used and absorbed by the body. Therefore, vegetarians should not panic. However, they must be careful to combine plant protein sources wisely. You need more vegetables to eat different amino acids.
Broccoli and cauliflower can often be consumed as they consist of approximately 40% protein. Vegans have to pay more attention to the fact that they ultimately have enough protein or. Vegetarians can also increase their net protein utilization and biological value by consuming a variety of protein sources throughout the day.
Raw yolk causes the gallbladder to contract, causing bile to be released into the intestines. It is used for medicinal and diagnostic purposes.
Chicken eggs have a beneficial effect on the nervous system. They are included in the diet for diseases of the nervous system, in the diet for therapeutic or preventive nutrition for people who work with mercury and arsenic. As a result of the combination of lecithin and iron in the egg, the hematopoietic functions of the body are stimulated.
Otherwise, you think you need enough protein, but ultimately not enough protein. Then it's time to wait: How much protein do I need to meet my needs? Since every food contains both protein, carbohydrates, and fatty acids, you can find out how much pure protein a food contains.
Note. Protein sources such as meat contain more fatty acids and less protein than before. This means that these protein sources contain less protein than we think. Just like people who don't move, animals who are only in a stall get a different ratio of fat cells: more fat, less protein. If possible, try to buy meat, dairy and eggs from animals that are constantly on the move.
Children can begin to be given chicken egg white only from the age of three. it is very allergenic. Allergenic properties are weakened by heat treatment of eggs.
If you are not allergic to eggs, then you should definitely eat them. Chicken egg white is the best and healthiest in the world. It is better than the protein of meat, dairy products or fish, because it is absorbed with virtually no residue. This is important for patients with skin diseases and patients with chronic dermatoses. Eggs are also beneficial for athletes who want to increase muscle mass. Protein is considered the best building material for muscles. Protein is also very beneficial for children and adolescents during their growth period.
You can use this chart to figure out if you have enough protein. Also pay attention to the biological value and use of pure protein. Eating 10 slices of bread with 40 cheeses daily means 80 grams of protein. However, the biological value is low, and in addition, this protein has low net protein utilization.
In addition, animal protein must always be heated, and this can lead to denaturation, where the amino acids cannot be used. Therefore, consuming only one animal protein should be considered for these reasons alone. Plant protein contains a lot of dietary fiber and low-saturated fatty acids and therefore also has fewer toxins. In addition, plant protein often does not need to be heated to allow optimal use of amino acids. Many patients with kidney failure have been advised to reduce their protein intake greatly. Now views seem to have changed: plant protein appears to place much less stress on the kidneys than animal protein. Therefore, kidney patients are advised to significantly reduce only animal protein. Especially if you belong to one of the groups that require more protein. Although they can consume protein, it must also be consumed in the digestive system. Without enough protein, our digestion may not function well; enzymes are essential for digestion and they depend on adequate protein. Poor stomach, intestinal, liver or pancreatic function, or leaky gut syndrome, can cause protein to be unable to be broken down into amino acids. The result may be bloating, rotting, allergies or intolerances. Knowledge for well-being and health - all recipes with a green symbol support healthy digestion. If changes in diet do not improve, see your doctor for orthomolecular medicine. Also note that many plant protein sources contain anti-nutrients and make plant proteins difficult to ingest and process. Too much animal protein at once or spread throughout the day can be difficult to digest. For example, breakfast with bacon and cheese, as an afternoon pizza with several types of cheese and meat, for lunch lasagna or a casserole with meat and cheese. Poor protein digestion or excess protein can lead to digestive problems and elevated urea and uric acid levels. In addition, excess protein can also carry excess weight. Proper preparation of protein sources is also important. So that these amino acids are converted into useful substances for the brain, muscles, energy, etc. We should have plenty of B vitamins, minerals, enough vitamin C, etc. take a good multivitamin as an adjuvant. It is even better to eat this daily, partly also raw food, so that the B vitamins and vitamin C are preserved.
- Diet variety is the best solution!
- Animal and plant proteins have their own advantages and disadvantages.
- Animal protein is typically high in saturated fatty acids and low in fiber.
- In addition, animals, like people, store various poisons in their fat.
We must remember that the protein of raw chicken eggs is poorly absorbed. It may also contain microbes that come from the surface of the shell. Before cracking an egg, rinse it under running water to remove germs. All eggs do not need to be washed after purchase, otherwise they will spoil even if they are stored in the refrigerator. It is advisable to store eggs in the refrigerator in special trays with the pointed end down. You should not eat eggs whose shells have broken. And in general, eating raw eggs is undesirable.
What does egg white consist of?
Clarity is an almost transparent substance that is primarily composed of water and protein, but also contains minerals and glucose. Of the proteins that make up an egg, more than half are ovalbumin. Ovalbumin is a protein of the serpin family and is considered one of the proteins of greatest biological value, as they contain approximately 385 amino acids and contain many of the eight essential amino acids.
What bad assimilation of raw clarity?
Serpins are a group of proteins that can inhibit the action of certain enzymes. In this case, ovalbumin is able to avoid the action of most peptidases, and the problem is its assimilation, which is not destroyed by these enzymes; the body is not able to assimilate the amino acids that make up ovalbumin.
What is protein denaturation
Proteins are very long chains of amino acids linked by bonds called peptides. These chains are arranged into more complex shapes called structures.A long time ago in America they started an anti-cholesterol campaign and banned the consumption of eggs. As a result, there were many more patients. Cardiovascular diseases, cancer, degenerative diseases have increased, and the number of people who are obese has increased. After this, America came to its senses and realized that they were doing something wrong. We conducted research and found that eggs have nothing to do with increasing cholesterol. So eggs are not at all harmful, but on the contrary, they are very useful. This is what it is, the protein of a chicken egg, the properties of which are so useful.
Structures are classified as: Primary: An amino acid sequence in linear form linked by peptide bonds. Tertiary: A chain of amino acids that has been folded before being folded again may be spherical, which is called a globular protein, or elongated, caused by a smaller fold, which is called a fibrillar protein. The manner in which a protein is adopted at this level depends on its biological function, so any change in the arrangement of this structure may result in a loss of its biological activity.
1. What is the role of proteins in the body?
Proteins perform several main roles in our body:
They are the material for the construction of all cells, tissues and organs;
Provide immunity to the body and act as antibodies;
Participate in the digestive process and energy metabolism.
2. What foods are rich in proteins?
Quaternary: This structure is rarely given and for what we are interested in it is not important. The only thing to remember is that it is connected by the same links as the tertiary. When we say that a protein is denatured, we mean that through agents, which may be physical or chemical, the bonds that hold the protein chain together in different conformations have been disrupted and that the protein has lost its spatial configuration and its biological function .
Now this only happens in the secondary structure, tertiary and quaternary, never in the primary structure, since the peptide bonds present only at this structural level are much more stable bonds than the rest and are not affected.
Meat, poultry, fish and seafood, milk and dairy products, cheese, eggs, fruits (apples, pears and pineapples, kiwi, mango, passion fruit, lychee, etc.).
Questions
1. What substances are called proteins or proteins?
Proteins are natural organic substances consisting of amino acids and play a fundamental role in the life of the body.
2. What is the primary structure of a protein?
The sequence of amino acids within a polypeptide chain represents the primary structure of the protein. It is unique to any protein and determines its shape, properties and functions.
3. How are secondary, tertiary and quaternary protein structures formed?
As a result of the formation of hydrogen bonds between CO and NH groups of different amino acid residues of the polypeptide chain, a helix is formed. Hydrogen bonds are weak, but together they provide a fairly strong structure. This helix is the secondary structure of the protein.
Tertiary structure is a three-dimensional spatial “packing” of a polypeptide chain. The result is a bizarre, but specific configuration for each protein - a globule. The strength of the tertiary structure is ensured by the various bonds that arise between amino acid radicals.
The quaternary structure results from the combination of several macromolecules (globules) with a tertiary structure into a complex complex. For example, hemoglobin in human blood is a complex of four protein macromolecules.
4. What is protein denaturation?
Violation of the natural structure of a protein is called denaturation. It can occur under the influence of temperature, chemicals, radiant energy and other factors.
5. On what basis are proteins divided into simple and complex?
Simple proteins consist only of amino acids. Complex proteins also contain carbohydrates (glycoproteins), fats (lipoproteins), nucleic acids (nucleoproteins), etc.
Quests
You know that the white of a chicken egg consists mainly of proteins. Think about what explains the change in protein structure in a boiled egg. Give other examples you know of where protein structure can change.
As a result of exposure to high temperatures, the protein denatures the egg. As a result of this, the protein loses its properties (transparency, etc.). Any heat treatment of food (boiling, frying, baking) leads to denaturation of proteins. As a result, proteins become more accessible to the action of digestive enzymes, but they themselves lose functional activity.
